Internet Explorer cannot display the webpage
Most likely causes:
You are not connected to the Internet.
The website is encountering problems.
There might be a typing error in the address.
It did this with all the betas including the latest IE 7 beta3 and I tried it on two PCs. I contacted one of the IE 7 developers from a Microsoft blog contact page, but never heard back. I've been too busy to contact my sources at Microsoft to resolve the issue. So for now I am forced to use Firefox any time I want to blog something. Not that I have a problem with that, but Firefox has its own issues with Movable Type - including an inability to search for text within Movable Type's fields, including the main Entry Body where you enter your blog's text. Editing the templates is also much harder in Firefox since you can't search for a specific piece of text in the template.
If I have time today I'll contact Microsoft and see what the deal is. Microsoft can't possibly release IE 7 without supporting the millions of Movable Type bloggers out there, can they?
Update: July 11th, 2006
I installed IE 7 beta 3 (after uninstalling beta 2) and the MT publishing issue went away.